Oscillograph



Aug. 9, 1932. 1 W, LIEGG 1,871,379

OSCILLOGRAPH Filed Deo. 29, 19,28 5 Sheets-Sheet l ffjg. 2.

lJose/Uh WLegg.

' ATTORNEY J. W. LEGG OSCILLOGRAPH Filed Deo. 29, 1929l s sheets-sheet 2 Fig. 4.

4o RPM. film. 48 RPM. Jill/fiez F1 g For 5,131 exposures 'fwzer 20% faster than film.

F195. For five el Fig. 'Z

posa/res v For five exposures 7711777 20? faster iban Shutter Film 2o7/aster zen @i/tref:

\ Pfff/7 im@ ofimemai gear 72 '7.' on shutter:

Pitch Zine afs/Jur w 60 7'.' onf/Im drum 50 RFE/1. Shaffer INVENTOR 6o Rem. film Josep/7 l/\/. Legg,

ATTORN EY Aug. 9, 1932.

evolution at ing of are las

Fig. lj.

for Cases: I

J. W. LEGG OSCILLOGRAPH Filed Dec. 29, 1928 3 Sheets-Sheet 5 Figa Fig. lo.

Film Faster; than l Film .SIowe/'Z/van .Shutter Shutter'.

Fig. 1.2.

Rari@ of Time Table in Seconds Dwaiian das@ swifehza Showing 5in/" of Zac/z 5111112141r -of 7n/lier Exposure. Expmure peed l. 2. .3. 4. 5. REM. Seconds d 0 1 2 3 4 60 0./67

b o 6 /2 /e 24 so 0./51 G 0 /l 22 33 44 60 0.167

d /:/6 o '/6 32 48 e4 so 0./67

INVENTOR Josep/v [M /Legg.

BY ATTORNEY- Patented Aug. 9, 1932 @punir-ED ist 'tias ,i

-JOSEPH W. LEGG, OF"WILKINSBURG, PEIINTNSYLVANIA, ASSIGNOR TC WESLNGQUSE -ELECTRIC @c MANUFACTURING COMPANY, A CORPORATIONFOF.-IBENNSYLVANIA oseILiJoGitAPH Application 1edDeoember-29, 1-928. Serial `No.''329,2173.

of a` galvanometer element.

5 When recording the characteristics of high lfrequency currents bythrowing a beam ofY light against a film and Vdeflecting lthe beam in accordance WithV the currentA variations, it 1s necessary Athat the film be moved past the 1C beam of `light at a high speed in-order to Ob-m' tain afrecordvshoiviiig sur'licient detail. #One of the mostsatisfactory Ways toi-moveI the film attherequired speed is to'attach the film tothe 4circumference of a rotatable drum and 1 15 thenfrotate tliewdrum; at high speed.'` 4This' fprocedure, however,.-ordinarily involves the disadvantage that: only one record can beob-H tainedion the iilm. I

`in obgect ofmy invention isl Jcoprovid-e a shutter-and-switching combination, in app f permit recording a plurality Vof high-speed oscillograrns on ay length offilinattached Vto the circumference of a rotating drum.. Y Another obJect of my invention 1s to provide a lamp-shiftcombination, in apparatus-l.

of the above-mentioned type, that shall fui"- ther increase `the number ofv oscillograms AWhich may be recorded ona film: drum.

vide means for accurately shifting an;os'cillo graph lamp through a ldesired path.

In practicing my invention, I employ arotatable film druni. positioned Within a rorotated either in the samedirection or inopposite directions but at different speeds. t.

the instant the shutter opens, orsoon-before7 a switch, connected to the drum shaft, initiy l `3 i While the ilm drum is being rotated.

@ther features and advantages ofmy inl `ventilo-n Will appear` 'from the Vfollowing decom Jani/fina drawings inv which J D D 7 af. ratus of the above-mentioned typefthat shall` tat-able shutter, .both the. drum andthe shutter Y Vbeu-.ig i located Within al light-proof casing.

In operation, the drum and the shutterlare f. threaded mechanism for shifting the lamp' `fscription, taken intconnection'with :the acav Figure 1 is aschematic-diagram offthe apiparatus' and electricall connectionsxeinployed in one embodiment of my invention, f

'Fig'.e is a: -vievv,.pa'rtly in sideelevationand partly in section,offfthe oscillograph optica-li System 1 and'oscillogr'aphA casing upon which v the film Vdrum and the-shutter sliovvn inl Fig. 41 are mounted, n V is aplan-,view of the lamp-shifting F ig. 3 structure, Fig. 4 is a vievv,l in-side el'evatio-i1,-of-l lamp-shifting Structure, y

Fig. -5 is a schematicfdiagrainoii thedrum andr shutt-ter combination shown-| in Fig. 1, 'Fig '6 is vieu?" siinilarI to that df Fig. 5"

but showing"the'shutterfopening in af'differenty --position rfvvith A respect totheA optical slotl Fig. 7^' is a schematic diagram of `av vinedi- V-icatioirofifthe drum'A and shutterl combina'f tion shown in Fig. 1,

Fig. '8f is -a schematic `diagram"of.afstill lfurther :modification of thev drinn and: yshutwter combination, p

Fig. '9 is adiagram showing the type of v record obtained When employinglthe Jinodif fication-sho-Wn in Figs. 5, 6 and 7.

- Fig. 10 is Vdiagram showing the type 0f n l ff record-:obtained when 'employing the modi- .Y `Another object of my invention is tol pro-A I fication shown inl Fig. v8, and

Figs.` 11-and 12i'are plan vievvs of chartsv Referring'toFig. 1, the apparatusv comprises a film drum 1,avshuttter 2a light Vproof casing'switches 4 and 5, an Oscillograph'lainp 6, andy anfassociated'electrical Vcircuit 7.l 'The film drum 1 isinouiited on a shaft Smotat'ably journalled in thelight.

prooi:l casing 3. There is anopening 9 iii the casing 3 for'admitting 'a beam'o'f light reflected from agalvanoineterv element f 10.

VThe kfilm drum Ylis rotated at a highy speed by means of a motor 11 connected to the shaft 8 Vby a belt 12 andpulley 13. Y TheV light-prooffcasing 3V is attached lto-an `0scillograph casing 14 (Fig. 2) by means' of the flanges 15 vas Will be more fully described hereinafter. Y p Theshutter 2, Which is rotatablyinounted CTI Y. zo

y60teeth, gear 19 has 72 teeth and on the shaft 8, comprises a cylindrical member 16 having enclosed ends and an opening 17 in the cylindrical wall thereof. rfhe shutter is rotated at a predetermined speed with respect to the film drum 1, by means vthe iilm drum rotates 20% faster than the fshutter.

The shutter 2 has a 60 opening 17, as shown in Fig. 5, which is a schematic dia-gram of the modification being described.

A beam of light is supplied to the gal# vanometer element 10 from a lamp 6 supported bya carriage 22 .which may be shifted Y bya threaded rod 23 journalledin suitable supports. The threaded rod 23 is rotated, simultaneously with the rotation of the film drinn. 1. byfineaiis'of vpulleys 24 and 25 and a belt26.`

Y' The combination 'ofthe oscillog'raph lamp r6, lampshifting mechanism, galvanometer 10 and film casing` 3 will be more fully understood' by referring to Fig. 2.V The lamp 6 and the galvanometer 27 are mounted within a light-proof ca -sing 14. The casing 14 is preferably constructed of a` sheet insulating material, such as fibrous material impregnated with a binder,.and comprises a base' plate'28, an end plate 29, side panels 30, a horizontal partition 31 and a single integral sheet 32 constituting'the top and the rear wall of the oscillograph casing.

A removable cover 33 is mounted over an opening`34 in the casing which permits an inspection of the lamp 6. The galvanometer 27. the detailed construction of which isfde-v scribed in my copending application, lSerial No. 757,586, filed December 23,1924. com- *as shown schematically in'Fig. 1, arranged prises'a fluid-tight casingf 35, disposed inthe lower rear portion of the oscillograph casing, containing a horizontally disposed galvanometer element 10 carrying a mirror 36,

beneath a lens or window in the upper wall portion 37 of the galvanometer casing. Terminals 38 are provided for thegalvanometer element 10. f l

The lamp 6 is slidably mounted on a structure attached to a side panel 30 of the oscil- .lograph casing 14, as will be more fully described hereinafter.

Alightshield 39, preferably constructed of relatively thin sheet aluminum. is of substantially funnel shape and rectangular in horizontal section. The shield is secured, at

`its larger end, to the horizontal partition 31 surrounding an opening therein. A plSlll O7 secured in position on the partition over the opening, directs the beam of light from the mirror 361througli a semi-cylindrical lens 41 toward a slot 42, hereinafter referred to as the optical slot, in the end plate 29. The opf tical slot 42 is in alignment with the opening 9 in the light-proof casing 3 so that the beam of light will strike the film drum 1 when the shutter f2 is open. ri'fhe lens 41 is clamped to a member 43 that is adjustably inouiited on the partition 3l by means of a screw which extends through a slot therein. lThis construction permits the beam to be properly focused through the slot 42 upon the film drum 1.

A member 44 of substantially U-shape,

preferably .constructed of sheet or strip material, is held in spaced parallel-plane relation to the outer surface of the end plate 29 by a spacer 45. The arrangement of parts permits the fianges 15` on the film-casing 3 to be slipped into position behind the member 44 to hold the film 'drum 1 in proper relation to the slot 42.

in electrical circuit 7 is associated with. the film drum 1 and the shutter 2 for lighting the oscillograph lamp 6 and initiating the electrical disturbance to be recorded at the instant the shutter opening 17 comes intok alignment with the optical slot y 42 and the opening9 in the light-proof casing 3. This circuit comprises two relays 46 and 47 having the windings thereof connected in parallel toa direct-current source of potential 48 throughconductors 49 and 51. A Vswitch 4, mounted on the shaft which rotates at the shutter speed, and a manually operable switch 50 control the continuity of the circuit. v

The rotating` switch 4 comprises a drum of insulating material with a strip of conducting material 52 attached to its circumference. The switch 4 is adjusted in such relation to the shutter 2 that it closes the circuit supplying current to the relays 46 and 47 an iiistant before an edgeof the shutter opening 17 rotates into alignment with the optical slot 42.

When the relay 46 closes', a circuit is completed through a conductor 53, source of current 54, the winding of a relay 55, a conductor 56 and the contacts of the relay 46. Thel relay 55 is thereby energized and the contacts thereof close an energizing circuit for acircuit-brealrer o4. .this circuit includes a conductor 58, the winding of the circuit- V62, and an oscillogram, showing the circuit breaker characteristics, is recorded on the i film? drum ,-14 by means of; .the galyanometen element` connected, across ,a current yshunt,

. 'i 63 in the `line61.

the film. yThe right-hand relay 47 is made i vT/Vhen the righthandrelay47 closes, a cir;

,.oscillo-graph lamp 6, gajbatteryl, aconduc-` vtor 66, and thecontacts of relay 4,7. A varif.y able resistance 6 7 isfconnectedacross.,the relaylcontacts in `order tokeep the filament of heated enough toemit light which will affect slow-actingto prevent-theoscillograph lamp `6 from-being lightedimuch: before the lelectrical ,s surge or. ydisturbance on jtheatransmis'- sion line 61is initiated. This arrangement is desirable because. of the ldelay due to the v`movement ofthe `mechanicalparts inthe i: .transient initiating circuit.

4 and, hence, isclosedonce every revolution of the shutter 2,ithje ilmfV drum 1,makes one 2l `Inv-.order-that apluraliy` of oscillograms,

2 f With he switch 50 closed, as shown, so that the relay rycircuit is controlledfbyv the .switch Vrevolution between successive exposures.-

showing the characteristics of circuit breaker f 62, may be recorded in rapid succession, it is n necessary that the circuit breakerl 62 be closed promptly after it is opened and before the shutter@ jopens for `the next exposure. This maybe accomplished eitherby, manually i lclosing `the circuit .breaker 62 or by aut-o- Amatically closing it in response to the-opening ofcircuitbreaker by means of aY relay i Vcircuit .and additional contactsjattached to Ycircuit breaker 57, in.` an obviousunanner.

By'opening the switch 5.0,a 'second rotating switch 5,1which closes,the-relayfcircuit only:

4p 2,. is connected into the circuit sc that the once during severalrevolutions of the shutter ilmfdrum 1 makes several-revolutions be- ...twe'en successiveexposures.;` The.frotating `switch is-driyen bya gear 68 in` engagement with a. pinion 69 mounted onthe samelshaft as gea-rs 19 and 20. v v v With the switch either opened or closed, the circuit above Ydescribed permits the., re-

, `cording of apluraliy of fhighspeed ,oscillof grams on the filindrum 1 with a definiteI time interval-eelapsing `between successive ex- .posures The operation of the shutter-2 will be more fully understood by referring to Fig. 5: vAs

and and the relays 46 and 47 are so adjusted .formerly explained,.the rotating-switches 4 so the period that the shutter opening 17 rotates past the optical slot 42. In the example il- H lustrated iny Figs. 1 and 5,(they shutter 2 and Hlm-drum 1 rotate in the same direction but at differentspeeds, the iilm drum 1 rotating 6? 20%4 vfaster than the shutter 2.; The design of the shutter v2 is1 determined by the-follows ing equations:

, `LetS-R. P. M. of slower member, `rcuit is completedthrpugha conductor, 64, the siert the faster; member ing .one exposure.

f chen s (1+ :n r.V M. of faster member lamp 6 slightlyheated at all times, yet `not :the fraction of the circumference `of passing optical slotfduractive vpart of the faster member dur-L and :fraction of circumference per l,=,1/; or 7 2c of circumference of film drum per exposure VA=15 or 60O opening of shutter.

If S 50 R, P. M..f0r the shutter s (1 +1-) :ce n. P. M. for the 51m.

Then 1.20 second=iti revolution of shutter.

v1.00;second=time required for one-revolution of film.

.0.20: (1.00% 5),y second=duration of each exposure.

c2c; (51.20%) shutter is open. Y

A`1.20-'.201fsecond=interval between ex- .posuresj f v 6.00. secondscomplete cycle of exposures. i. Assuming thefilm to be unexposed when in the position shown in Fig. 5, if ythe shutter rotates one rotationsegment No. 1' of the 1ilm is exposed, since this portion ofthelilm second.=the. period. .the g;

has rotated past the optical slot 42 during the time the shutter opening 17 wasrotating past the optical slot 42. After the shutter 2 has completed one rotation, it is again in theposition shown in thevfigure. The iilm drum 1, however, has rotated 1 and 1/5 times faster than the shutter 2-,and, at the end of one rotation of the shutter 2, is positioned with No. 2

segment of thelfilm in the position in `which segment No. 1 is shown in the iigure. At the end of a secondretation ofrithewshutter2, segment No. 2 of the lilm has been exposed and segment No. 3 is in position to be exposed during the next rotation of the shutter 2.

' lff the film-'drum 1- and the shutter 2 shown in Fig. 5 are rotated in opposite directions, instead ofy in thesame direction, the operation of the shutter willI not be changed. This .fact will be `readily.understood by. referring to Fig. 6,1 in which figure the film drum l1 and theshutter 2 are shown inposition for .the

start ofthe first exposure, the operation being the same as that described above.

In one modification of my invention, the shutter 2 may be omitted, and the rotating switch 4 and a suitable oscillograph lamp 6l employed instead. It is obvious that, if the oscillograph lamp 6 lights quickly and goes out quickly, there is no need for a shutter. A lamp especially suitable for this modifica- `tion is one having a fine ribbon filament supported by heavy lead-in conductors. It will "'3 modification for recording voice-currents by continuously actuating the galvanometer element 10 in accordance with voice waves while the shutter 2 permits only a portion of the waves to be recorded. It should be noted, however, that utilization of a rotating switch for lighting the lamp 6 only during the period the shutter 2 is open will prolong the life of the lamp.

The modification shown in Fig. 7 operates the same as that shown in Fig. 5, but a different means for rotating the film drum 1 and the shutter 2 at the proper speeds is employed. Instead of employing the gear train shown in Fig. 1, an interna-l gear attached to the shutf5 ter and a spur gear attached to the film drum are employed, as indicated.

In the modification shown in Fig. 8, the shutter is rotated 20% faster than' the film drum.' The design of this modification is Adetermined by the general equations previously given. Y

llhereV six exposures are to be obtained with the shutter rotating 20% faster than the film drum (as in Fig. 8), the design is determined as follows:

1 l or 72 opening m shutter.

1 o y :1/6 or 60 arc per exposure of film.

If 3:40 R.P.M film drum S 1 =48 n rM. Shutter.

1.50=second per revolution of film. l 1.25=second per revolution of shutter. 125+ 5:0.25 second per exposure (duration). Y y

l1;25-O.25=1 second interval between exposures. Y

In this modification also, the shutter and drum may be rotated either in the same direction or in opposite directions. The opv eration is substantially the same as that describe-d in connection with Fig. 5.

The modification shown in Fig. 8 is not the preferred form, since Vthe records obtained by rotating the film drum faster 'than the shutter are more easily read. Thisis evident by comparing Figs. 9 and 10 in whichthe numerals indicate the order in which the exposures are made while the arrowsindicate the direction in which each record should be read. The five recordsl shown in Fig. 9 may be readfrom top to bottom without interruption. Those shown in Fig. 10, however, must be read from the bottom of the first exposure to the top, then from the bottom of the second exposure to the top. g

As previously pointed out, the switch for closing theoscillograph-lamp and transient or .surge-initiating circuits may be rotated at a slower speed than the shutter. Such a slowrotating switch 5 is shown in Fig. 1 connected in series with the switch 4 which rotates at the shutter speed. -When the yswitch 50 is opened, the circuit supplying current tothe relays 46 and 47 is closed only when the slower switch 5 is closed. The ratio of the speed ofthe slower switch 5 to thatof the .shutter should equal m where E equals lamp 6 had been lighted each time Vthe shuti ter 2 opened. f It should be noted that a may equal any whole number.

Fig.l 11 shows a chart indicating the time, vwith respect tol the rotation of the shutter and film drum that the exposures are made for cases a, 5,0, and CZ. Each case is'for a different ratio of switch to shutter speed. This chart and the one shown in Fig. 12 are -for the modification illustrated in Figs. 1 and 5. f

Fig. 12 shows a supplementary chart for cases a, b, c, and d which gives the time, measured from the beginning of the first exposure, that each exposure begins. This chart shows the ratios of kswitch to shutterV speed (the ratio for the cases a, b, G, and d.

It also showsthe duration of an exposure. i

YIn the above-mentioned charts, case a is the one where the switch 50, in the modification illustrated in Fig. 1, is closed. Case b is the one where the switch 5,0 is open and the gear ratio of pinion 69 to gear 68 is 1 6.

The utilization of the more slowly Arotating switch 5 permits a greater film-drumspeed lamp 6, while an oscillogram is'being rethan the two holes in `the Aleft-hand end' 'oi'.

corded, is shown' in Figs. 2, 3 and'li. "TheVlr lamp""6"issupported Vby means `of a member' 7 0 oU`shape attached to a carriage 7l (coreA respondingto carriage' 22 inFig; l) which isV slidably mounted upon rods 72. lThe rods 72V are supported at one end by means of a splitH strip 73, one endoi which is attached to the j sidepanel 30 ofthe'oscillograph casingit by means ofscrews74, as indicated in Figs. 2-

and. The otherends of the rods'7 2 are sup# ported by means of the side panel'BO.

The carriage 7l is provided with a central portion 5 having the' free end thereoiJ bent' downwardly and provided with a tapped hole extending therethrough. A threaded rod 76, journallediii abearing 77 mounted in theside panel 30, lcooperates'with 'the threaded hole of the' carriage 7l to move the carriage along the rods 72 as the threaded rod olf the carriage are so drilled thattheylike-T wise havea tendency vvto spread apart'.` This result is accomplished by' drilling the two" holesin the left-hand" end Aof the split strip art'herapart thanthejjtwo holes in the panel 8O into'w'liich'lthe right-hand ends oitV the rods 72 Vare bolted. The holesin the left# handend of thecarriage 71,throiigh:whichV the rods-72' extend, 'are drilled the samedis tance apart as the above-mentioned two holes inthe'panel 30. The holes in the rightehand' exibleend of the carriage l, through" which the rods 72 extend,are drilled `farther apart the carriage.VA Obviously, whenA the*` carriage is mounted onthe rods,they are'held parallel to each othei', although the rods/72 and'ijiglithandpieces of the carriage 7l have atendlv ency' tospread." f n f p ,Y Springs 78-are provided on therods 72 at the ends thereof` so that, when the threaded rod 76 is 4turned far enough in either, direc" tion to run the bent=down threaded portion p of the carriage 7l off'the threaded part of the rod 76,'saidbent4down portion'will be held against' the shoulder of the threaded partoil the rod7 6 by `meansl of the springs 78 ilhe Alamp vterminals 7.9 are connected toV binding posts by means of iexible conductors 80, as shownin Fig.v 2." By shifting the lamp 6 as described, the light beam makes a spiral path on'the nlm so that the number of reci ords'y that may be made on the nlm drum is greatly'increased structure of the character above describedV is found' necessary ftrshifnng 'the lamp, since a slight deviation' of the lainpf able error in the record.

vWhile it would be possible to make' asimi-- Ylar spiral .record by shitting the ilm drum,

from the desired path 'will-'cause anapprcoi'f "if instead of the loscinogi--aph iam p, the appara-ff tus would be cumbersome because of the rela.- ltively arge ysize oi' the iilm drum.

Various modiiications maybe made iii'my invention Without"departing ili'om the spirit yandv scopethereo' and desire, therefore, Vti'iatoniy such limitations shall' lbe-f'place'd thereon as are shown by tliepiior art and i setmrorth iii the appended claims.

i claim as my invention:

l. Recordingapparatus comprising arotatabie cylindrical member adapted to carry a light-sensitivel material on its circumference, means 'for moving a beam oi-light trans;y

versely' to the rotation oi?v said"cylindrical v "member and in accordance Vwith 'tlievarii ations of quantity, and Vmeansresponsrv-e to the'v rotation of *the said '.cyliiidrical l oif portions of'saidcylindrical member to "said f member for successively exposing a vplurality light beam and 'for rotatingfsaid 'cylindrical f 'i "member at least one revolution'betvieen"suc` vl cessive exposures.

`2. `Recoidi'ng apparatus c0lnpri$`ing iin-"95I tatable cylindrical member" adapted'to carry'f a light-sensitive material-on its circum'fer-y ence, means for moving a beainoi light trans-'fV d. Y `verrsely to the "rotation" or' said `'cylindricalf 'i member vand in accordancejwiththe variationloo j 'Y of a `quantity,and'ineans i'or exposing suc-1V 4 cessive portions of said light-sensitive ina.-V terial, the length' oi said portion fraction of the diical inemben 3. Recording apparatus comprisingard tatabvle'v cylindrical member adapted to Carry l a lightlsensitive materialien its circumfe'rf-H ence, means for moving a beam of lightftrans- Vi i* Vv'versely 'tothe rotation of said cylindrical l member and in accordance'with the `varia` tion of a quantity, and means for exposing""' 'i [successive portions of saidllight-sen'sitive ma-V terial while said' cylindrical memberfis' rotatin'g` at a uniform ,high speed, 'the timei'- Vterval between exposures being greater'than the time interval during an exposurev Recording apparatus comprising azro-V tatable' cylindrical member'adapted to'fcarry a light-sensitive materialon its circumfer-K v ence, meansfor moving abeamlof light transf' fizo Vcrsely' to the rotation'of said cylindrical" light zbeamupon a lportion of said"cyliii` drical member during a fraction of a revolu-A VDflember andiin accordance with the` Vaa;

tions, of a quantity means for impressing Sal l rtion of said'inemb'er, and means responsive i" ,to the rotatie-n Vor saidicyiindrieai member for impressing ysaid light beam upon afpory o,

ltion of said member adjacentto said Yfirst v vbeam of light when saidniember has made'at least one complete revolution after said first exposure. y

6. Recording apparatus `comprising a hollow Acylindrical member having an opening in the wall thereof, a film drum positionedv within said member, and means for Vsiinultaneoiisly rotating said member and said drum at different speeds.

7. Recording apparatus comprising a hollowcylinder having an opening in the wall thereof, means for rotating said cylinder, a cylindrical member positioned within said cylinder, and means for rotating said cylindrical member at a higher speed than said hollow cylinder.

8. In a system having means for vibrating l a beam of light in accordance with the vibrations of a quantity, a cylindrical membercarrying a light-sensitive material, means for rotating saidY member, means for exposing said material to said beam of light for a Iracv tion of a revolution only of said member, said means comprising a rotatable circular ele* ment having asegment along its circumferencek which permits said beam of light to reach said cylindrical member during the time said segment passes a fixed point, means for rotating said element slower than said cylindrical member, the length of Vsaid seg- 360 ment. beingV equal to m Where N equals the reciprocalof said fraction of a revolution. i 9. Recording apparatus comprising a rotatable Vfilm drum, a light-proof casing en'- closing` said drum and having an opening therein for admitting a beam of light, means,

including a rotatable switch, for controlling .said beam of light, and means for rotating said switch at a different speed than said film drum;y Y

10. Apparatus for recording successively occurring electrical phenomena comprising a rotatable film drum, a rotatable switch, means for rotating said drum and said switch at,l different speeds, means, including said switch, for periodically lighting a lamp and for creating an electrical disturbance, and means, including said lamp and a galvanometer element, for recording said disturbances on said film drum. Y f j 11. Recording apparatus comprisinga hol: low cylindrical member havingan vopening in the wall thereof, a film drum positioned within said member, means for rotating said member and said drum at different speeds,

means,7inc luding an incandescent lamp, for moving a lightr beam transversely to the-rotation of said drum in accordance with variations of a quantity, a light-proof casing enclosing said cylindrical member Vand saidl film drum and having an opening therein` for admitting said light beam, and means for Y lighting said lamp only during the period said cylindrical-member opening is rotating past the opening in said light-proof casing. l2. Recording apparatus comprising Va rotatable film drum, means, includingy a lamp,

for throwing a beam of light upon said drum and for defiectiiig said beam in accordance. with vvariations of a quantity, and means forshifting said lamp transversely to therota tion of saiddrum. Y

13. Recording apparatus comprising a rotatable film drum, means, including a lamp,

Vfor throwing a beam of light uponsaid drum and vfor deflecting said beam'in accordance with variations of a quantity, and means, responsive to the'rotationof said drum, .for shifting said lamp transversely to the rotationA of said drum.

lll. Recording apparatus comprising a rotatable drum adapted to carry light-sensitive material on its circumference, means, including a lamp, for throwing a beaml of light"1 7 upon said vdrum andfor deflecting said beam in accordance with the variations of a quantity, means for shifting said lamp transverse-y ly tothe direction of rotation of said drum, and means forexposing successive portions ofsaid light-sensitive material, the length of said portions being a fraction of the circumference of said drum.

miA

15. Recording apparatus comprising a rotatable lm drum, means including a lamp, for throwing a beam of light Vupon said drum and for deflecting said beam in accordance. with -variations of va quantity, means for shifting said lamp transversely to the direction of rotation of said drum, and means for successively exposing a plurality of portions iis of lsaid film drum to said light beam and `'for ,rotating said yfilm drum at least one rotation between successive exposures. y

16. In apparatus comprising a cylindrical member carrying a light-sensitive material on its circumference and means for throwing a beam of light upon said material, the

method ofrecording deflectionsof said beam of light which comprises rotating said member, throwing said beam of light upon said member for a fraction of a rotation of said member, whereby a portion'of said material is exposed, rotating said member at least one complete rotation at the end of said exposurel ,e

and again throwing said beam of light upon said member for a fraction of a rotation of said member.

17. In apparatus comprising a cylindrical member carrying a light-sensitive material on its circumference .and means for throwing a beam of light upon said material, the

method of recording deleetions of said beam s of light which comprises rotating saidV member7 throwing said beam of light upon said member for a fraction of a rotation of said member whereby a portion' of said materialV is exposed, rotating said member an integral number of rotations at the end of saidA eX'- posure, and again throwing said beam of light upon said member for a fraction of a rotation of said member.

In testimony whereof, I have hereunto subscribed my name this 28th dayof December,

JosEPi-i w. Liiee. 

